1. Field of the Invention
The present invention relates to a camera, and more particularly, a camera that uses film with a recording area in which information is recorded or a Patrone and that can record position measurement data indicating a photographic position or place name data in the recording area.
2. Description of the Related Art
In recent years, many proposals have been made for a camera using film with a recording area in which photographic information and other information are recorded on a Patrone. Various proposals have been made for a camera capable of magnetically recording photographic position information representing places of photography as the photographic information in association with frames on film. In this kind of camera, a receiving means incorporated in the camera fetches position measurement data indicating a photographic position, and the position measurement data is recorded in a magnetic recording area of film.
A camera capable of recording position information has been disclosed in Japanese Patent Laid-open No. 4-70724, wherein a global positioning system (GPS) receiver is incorporated, and position measurement data received by the GPS receiver are automatically recorded in a recording area of film in one-to-one correspondence with film screens. The GPS is a high-precision position measurement system, wherein a receiver on the Earth receives data transmitted from four satellites, and time intervals required for receiving the data are measured to calculate a three-dimensional position of a place in which the receiver resides.
A camera capable of recording position information, which has been disclosed in Japanese Patent Laid-open No. 4-70735, includes a position measurement means that is the. GPS receiver, and a place code receiving means that receives place codes sent from a resort or an event hall. When such a place code can be received, the place code data fetched by the place code receiving means is recorded in a recording area of an associated frame on film. When a place code cannot be received, the position measurement data fetched by the GPS receiver is recorded in the recording area of an associated frame on film.
The cameras capable of recording position information, which have been disclosed in the foregoing Japanese Patent Laid-open Nos. 4-70724 and 4-70735, cannot fetch position measurement data sent from the GPS or place code data sent from a place code transmitter in a place where radio waves hardly reach; such as, under the shade of an obstacle, inside a building, or in a basement, and therefore cannot record the place of photography in an associated frame.
The GPS or a position measurement system based on satellites will be described in detail.
As for the position measurement system based on satellites, the navy navigation system (NNSS), navigation system with time and ranging/global positioning system (NAVSTAR/GPS), GEOSTAR system, and Ommi TRACS are well-known.
In recent years, it has been expected that the GPS will grow into a globally-usable position measurement means. In the GPS, when radio-frequency signals are received from three satellites out of a total of 18 satellites that are put in six orbits in threes, distances from the satellites are calculated to work out a latitude and longitude on the Earth. Furthermore, when radio-frequency signals are received from four satellites, an altitude as well as a latitude and longitude can be calculated. "Sensor Technology" (page 33, Jan. 1991), a Japanese publication, carries the detailed description of the GPS.
FIG. 20 is a block diagram of a GPS receiver that receives radio-frequency signals within the GPS.
An antenna 230a receives radio waves transmitted from NAVASTAR satellites which are not shown. The antenna 230a is, for example, of the quadri-filar helix type. A radio-frequency signal received by the antenna 230a is fed to a mixer 230. A modulator 231 diffuses a local oscillational signal CK1 sent from a local oscillator 232 with a PN-code signal sent from a PN code generator 233. The diffused modulated signal is fed to the mixer 230. With the modulated signal, the radio-frequency signal is converted into an intermediate-frequency signal. The intermediate-frequency signal is then fed to a data demodulator 234. The data demodulator 234 demodulates data that are placed on an input signal and include a time instant at which a satellite transmits a signal. The demodulated data is fed to a data processing circuit 235 and a delay measuring circuit 236.
With the input of the demodulated data, the delay measuring circuit 236 outputs a timing signal to the PN code generator 233. The PN code generator 233 incessantly generates a PN code in response to a clock pulse CK2 sent from a PN-code clock generator 237. With the input of the timing signal, the PN code generator 233 sends generated PN codes to the delay measuring circuit 236. A PN code provided by the data demodulator 234 and a PN code generated by the PN code generator 233 are routed to the delay measuring circuit 236. A delay time required for a PN code to correlate with the other PN code is measured. The delay time for a PN code is measured by counting high-frequency clock pulses CK3 generated by a measurement clock generator 238. The delay measuring circuit 236 supplies the count value as delay data required for the PN codes to correlate with each other to the data processing circuit 235.
The data processing circuit 235 comprises microprocessor and is driven with a clock pulse CK4 sent from a data processing clock generator 239. Using the transmission time instant data contained in the demodulated data sent from the data demodulator 234 and the reception time instant data sent from cesium and rubidium steam atomic clocks, which are not shown, incorporated in the GPS receiver, the data processing circuit 235 calculates a distance from the satellite to the GPS receiver (camera). The data processing circuit 235 computes the distance information from satellites and the position information of the satellites contained in demodulated data, calculates position information concerning the latitude, longitude, and altitude of the camera (photographer), and then outputs the position information to a CPU 200.